1. Field of the Invention
The present invention relates generally to the field of heating and cooling systems for multi-tenant buildings and more particularly to a system for monitoring energy use and for allocating the expense thereof pro-rata among said tenants.
2. Description of the Prior Art
It is generally known in the operation of apartment houses and commercial buildings that when individual tenants are responsible for payment of heating and cooling expenses the energy costs for the building are less than when such expenses are included in the rental. Where the entire building is heated and cooled by a common heating and cooling system, allocation of energy costs among the various tenants according to their respective energy usage requires a system for accurately monitoring such usage.
Prior to the present invention various systems have been devised for the purpose of monitoring energy usage. Typical of the prior art are U.S. Pat. Nos. 4,002,890 and 4,234,927. Each of these systems require that the temperature in each apartment or commercial unit be monitored. To this end one or more temperature sensors must be located in or near each unit such as in the return air plenum. Each such sensor must be coupled to a remote working location for processing. While such systems could conceivably be installed with relative ease during the construction of new buildings, the same is not true of existing structures.